I have a Kubota mower deck RC60-71B, the gear box oil leaked out and I need a top bearing (first one to overheat) and the oil seal at the bottom of the gear box (where the oil leaked out). I have removed the top bearing no problem, but I can't tell just what to do next to remove the lower bearing(?) to get to the oil seal. Can anyone help me with a short step-by-step explanation?

Answer: remove (4) gear box mounting bolts #310 and the gear box just lifts straight up, and the lower bearing and oil seal comes up and out with the gear box; and the pulley and pulley drive shaft #250 remains in place. You may need to pry slightly between the bottom of the gear box and the top of the pulley to break the slight adhesion between the lower bearing and oil seal, and the pulley drive shaft.

OK, starting to feel a bit like I'm talking to myself but I'm going to post this in case it is useful to someone else. I got the gear box off. The shaft stays with the gearbox on the RC60-71H. First, take off the blade and associated washers. Then remove the circlip and the splined boss on the shaft. On mine the circlip was missing and the boss would not pull off. The next step is to remove the four bolts holding the gearbox on. Having done that, I was able to encourage the shaft and gearbox upward (block of wood and large hammer) driving the shaft up through the boss, at which point the gear box was off. It goes now to the dealer to have the bearings and seals replaced. I feel confident I could do that but they said it is just about one hour labor plus parts and I think it would take me a few hours at least and probably multiple trips for parts, tools (I would need large circlip pliers for this job) and supplies. And it will be good to develop a relationship with the local dealer.

Project completed. Cost to have the dealer replace all the bearings in the gearbox and refill with oil was $139. While the gearbox was off I had a local welding shop do major reconstructive surgery on the swiss-cheese portions of the deck. They also primed it, cost $150. So, about $300 total (add $4 for a can of orange spray paint from WalMart and a few bucks for miscellaneous parts) and I'm back in business. I think this was a good way to do it, although in retrospect it might have made sense to go the extra $25 and get a new belt, then keep the old one as a spare.

Here is a "before" picture showing some of the problem:

Here are a couple of "after" shots:

I'd say it looks a bit better in the pictures than in person, but I think it will serve me well for a while longer. And now I need to catch up with the mowing. Fortunately I was able to keep up with the small stuff with my old Murray riding mower, but the bigger fields are calling to me.

One thing about it, that $300 is about a third of the cost for a cheap rider at Walmart. Your Kubota will last five times as long, with minimal maintenance. Bigger decks tend to make more even cuts also.

I am glad that my Woods deck has a belt drive vice a gearbox located under the tractor.

I have a Kubota mower deck RC60-71B, the gear box oil leaked out and I need a top bearing (first one to overheat) and the oil seal at the bottom of the gear box (where the oil leaked out). I have removed the top bearing no problem, but I can't tell just what to do next to remove the lower bearing(?) to get to the oil seal. Can anyone help me with a short step-by-step explanation?

Just replacing the bearings and seals will correct SOME of the out-of-balance play and vibration; but not all of it. The gearbox input shaft is very poorly-designed: supported by two 6205 [25x52x15] ball bearings, that are mounted virtually back-to-back. There is only 9/16" separation between them; so their resistance to sideways forces is minimal.

And those sideways forces can be considerable, since the PTO shaft typically operated at an angle about 15 degrees, in the case of my mower. So the bearings wear out quickly, and the resultant play wrecks the seals. Then the oil runs out; and the gearbox seizes. LOVELY . . . .

UPGRADES
1: Make sure the bearings you fit are close-tolerance: at least ABEC-3; preferably ABEC-5. And close fit as well: CM or CN, rather than the usual C3 [loose fit]. That will help - for a time.
2: Replace the ball bearings with cylindrical roller bearings: flanged NJ205 bearings are 25x52x15, so will fit right in. Limited resistance to axial thrust; but much higher sideways resistance.
3: Do away with the oil seal, and replace it with ANOTHER bearing, with its own oil seals. That's a 6205 2RS. That means leaving out the internal circlip, drilling and tapping 5/32" holes around the end face of the gearbox housing casting [I drill 6; you could go to 8]. Making up a clamp ring-plate to bolt round the shaft and onto the casting end. Using that to clamp and hold in the outer of the TWO bearings. If you want, you could then make the inner of the two bearings an NJ205 roller, for more strength - since the two ball bearings will take care of end thrust.
Finally, if you want to back up the built-in seals in the 6205 2RS, you can take a standard 25x52x10 oilseal, grind off the sidewalls [leaving just the flat disc] and install that under the clamp plate as an additional seal.
4: Carry out the same gearbox housing modification as [3] above. But, in place of an extra bearing replace BOTH ball bearings with Taper Roller bearings. The 30205 is 25x52x16.25 so, to get the gear wheel properly positioned, you have to machine 1.25mm off the inner and outer shells of the inside bearing. If you take a wider 25x52x22 taper roller for the outer bearing, and add a 10mm oilseal, that will protrude from the housing, and you use the ring clamp frame to apply the necessary preload - through the oilseal - for the taper rollers.

Four solutions, in rough order of effort needed, and resulting strength.

But God knows why Kubota made such a crappy design in the first place . . . .